JP2012103494A - Dry film resist, support film for dry film resist, and manufacturing method of circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dry film resist suitable for effectively manufacturing a circuit board such as a printed wiring board where higher resolution is required, and a support film suitable for the dry film resist.SOLUTION: Provided are a dry film resist having a support film, a resist layer which is at least one side of the support film, and if desired, a protective film, where the support film is a film containing a polyglycolic acid having 70 mol% or more of a glycolic acid repeating unit represented by the formula -(O-CH-CO)- or a laminate film of the film with a film containing another polymer; a support film for the dry film resist; and a manufacturing method of a circuit board using the dry film resist.

Description

  The present invention relates to a dry film resist formed by laminating a support film, a resist layer, and a protective film in this order. Specifically, the present invention relates to a dry film resist provided with a support film excellent in light transmittance and releasability from a resist layer, a support film for dry film resist, and a circuit board using the dry film resist. Regarding the method.

  Conventionally, a photoresist method using a photosensitive resin has been used to manufacture a circuit board such as a printed wiring board. That is, it is a method of laminating a photosensitive film on a base material provided with a metal layer such as copper foil, developing after exposure through a negative film (photomask), performing plating in some cases, and then performing etching, resist stripping, etc. .

  As a photosensitive film used in the photoresist method, a dry layer having a multilayer structure in which a resist layer (photosensitive resin composition layer) is laminated on at least one surface of a light-transmitting support film and a protective film is provided on the resist layer in some cases. A film resist is used.

  The method of using the dry film resist for the production of the circuit board is as follows.

  When the protective film is provided, the protective film is first peeled off, and then the exposed resist layer is attached to a metal layer such as a copper foil of a base material for circuit board production. In this state, a negative film (photomask) in which a predetermined pattern is formed on the support film is brought into close contact, and actinic rays such as ultraviolet rays are irradiated from the negative film (photomask) side. Is exposed to a predetermined pattern and cured, and then the negative film (photomask) and the support film are peeled off. A solvent (developer) is applied thereto by spraying or the like, and a resist image is formed (developed) by removing the uncured resist corresponding to the unexposed portion. Then, etching is performed using an aqueous cupric chloride solution, and the metal layer such as the copper foil that was under the uncured resist at the time of actinic ray irradiation is removed. Then, the cured resist is removed, and if necessary. Generally, a method of forming a circuit having a predetermined pattern using a metal such as a copper foil by plating is generally performed.

  In particular, in recent years, from the viewpoint of environmental problems and the like, there have been increasing use of a weak alkaline aqueous solution as a developer for removing an uncured resist. Further, a strong alkaline aqueous solution is often used to remove the cured resist.

  In order to cure the resist layer in a predetermined pattern, actinic rays such as ultraviolet rays are irradiated through the support film of the dry film resist. When the transparency of the support film is low, the resist layer is not sufficiently exposed or light is scattered, resulting in a problem that the resolution is deteriorated. Therefore, since the support film is required to have excellent transparency to actinic rays such as ultraviolet rays, high transparency and low haze value, conventionally, a polyester film has been used, and in particular, excellent mechanical properties. Therefore, a biaxially stretched polyester film is often used.

  In recent years, there has been a demand for higher resolution by miniaturization of printed wiring board circuits, liquid crystal display wiring applications, and direct mounting of semiconductors. Therefore, it is required to improve the transparency and transparency of the light, particularly to improve the transparency of the actinic ray in the short wavelength region. However, if a polyester film, particularly a biaxially stretched polyester film, is used as the support film for the dry film resist, and the transparency and permeability are further improved, the slipping property of the support film deteriorates. There was a problem that scratches were likely to occur, the winding property and running property of the film were lowered, and wrinkles were generated on the film.

  In order to solve this problem, a method (see Patent Documents 1 to 3) in which inorganic or organic particles are contained in a polyester film or a laminated polyester film is further proposed. Further, a method has been proposed in which the light transmittance at a wavelength of 365 nm is set to 80% or more by reducing the polyester polycondensation metal catalyst residue (see Patent Document 4). However, even these methods are not yet fully satisfactory.

Japanese Patent Laid-Open No. 10-46012 Japanese Patent Laid-Open No. 7-333853 JP 2001-117237 A Japanese Patent Laid-Open No. 2004-115566

  The subject of this invention is providing the dry film resist suitable for manufacture of circuit boards, such as a printed wiring board for which higher resolution improvement is calculated | required.

  In particular, an object of the present invention is to provide a resin film that is suitable for the support film of the dry film resist and that can be made degradable such as biodegradable.

  Another object of the present invention is to provide an efficient method of manufacturing a circuit board that can achieve higher resolution by using the dry film resist.

As a result of intensive studies to solve the above problems, the present inventors have a glycolic acid repeating unit represented by the formula-(O.CH ₂ .CO)-as a support film of a dry film resist having 70 mol% or more. It has been found that the problem can be solved by providing a film containing polyglycolic acid (hereinafter sometimes referred to as “PGA”), and the present invention has been conceived.

That is, according to the present invention, a support film and a dry film resist having a resist layer on at least one side of the support film, wherein the support film is a glycol represented by the formula — (O · CH ₂ · CO) — The dry film resist is characterized in that it comprises at least one film containing PGA having an acid repeating unit of 70 mol% or more.

  Moreover, according to this invention, the dry film resist of the following (1)-(5) is provided as an embodiment.

(1) The said dry film resist which has a protective film on the opposite side to the support film side of a resist layer.

(2) The dry film resist described above, wherein the support film contains polylactic acid in addition to the PGA.

(3) The said dry film resist whose support film is a laminated film provided with the film containing the said PGA and the film containing another polymer.

(4) The dry film resist as described above, wherein the other polymer is at least one selected from the group consisting of polylactic acid and polyethylene terephthalate.

  Moreover, according to the present invention, the dry film resist support film containing the PGA, the film containing the PGA, and the laminated film including a film containing another polymer A support film for a dry film resist is provided.

  And according to this invention, the manufacturing method of the circuit board which uses the said dry film resist is provided.

  According to the present invention, it is possible to provide a dry film resist suitable for manufacturing a circuit board such as a printed wiring board for which higher resolution is required. In addition, according to the present invention, by using the dry film resist described above, there is an effect that a method for manufacturing a circuit board that realizes higher resolution is provided. Since a circuit pattern can be formed by irradiating light, an effect that a finer circuit pattern can be formed is produced. In addition, according to the present invention, the support film and the resist layer can be easily peeled, and the support film peeling step and the uncured resist removal step (development step) can be performed simultaneously. Manufacturing can be carried out efficiently. Furthermore, according to the present invention, since it is possible to obtain a support film of a dry film resist that can be decomposed such as biodegradation, there is an effect that the environmental load can be reduced.

1. Polyglycolic acid The dry film resist of the present invention comprises, as a support film, at least one film containing PGA having a glycolic acid repeating unit represented by the formula-(O.CH ₂ .CO)-at least 70 mol%. It is.

The content ratio of the repeating unit represented by the formula-(O.CH ₂ .CO)-in the PGA contained in the film needs to be 70 mol% or more when the total monomer unit of PGA is 100 mol%. Yes, preferably 85 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, particularly preferably 99 mol% or more, and the upper limit is 100 mol%. Therefore, PGA includes a homopolymer of glycolic acid composed only of glycolic acid repeating units represented by the formula-(O.CH ₂ .CO)-(a ring-opening polymer of glycolide which is a bimolecular cyclic ester of glycolic acid). And a PGA copolymer containing 70 mol% or more of the glycolic acid repeating unit.

When the content ratio of the repeating unit represented by the formula-(O.CH ₂ .CO)-of PGA contained in the film is less than 70 mol%, excellent transparency and biodegradability are deteriorated. If the content ratio of the repeating unit is 70 mol% or more, it is possible to control the crystallinity of PGA by introducing a small amount of a copolymerization component as other components, thereby lowering the extrusion temperature and improving stretchability. It becomes. In addition, when a small amount of a copolymer component is introduced into the PGA, when forming a support film for a dry film resist, which is a laminate film including a film containing the PGA and a film containing another polymer as a support film, It is also preferable in that it can improve the adhesiveness and adjust the extrusion temperature of coextrusion.

  Examples of comonomers that give a PGA copolymer together with glycolic acid monomers such as glycolide include ethylene oxalate (ie, 1,4-dioxane-2,3-dione), lactides, lactones, carbonates, and ethers. , Ether esters, amides and other cyclic monomers; lactic acid, 3-hydroxypropanoic acid, 3-hydroxybutanoic acid, 4-hydroxybutanoic acid, 6-hydroxycaproic acid and other hydroxycarboxylic acids or alkyl esters thereof; ethylene glycol A substantially equimolar mixture of an aliphatic diol such as 1,4-butanediol and an aliphatic dicarboxylic acid such as succinic acid or adipic acid or an alkyl ester thereof; or two or more of these Can do. Among these, cyclic compounds such as lactide, caprolactone and trimethylene carbonate; hydroxycarboxylic acids such as lactic acid, and the like are preferably used because they are easy to copolymerize and easily obtain a copolymer having excellent physical properties. These comonomers can be used as a starting material for giving a PGA copolymer together with the glycolic acid monomer such as glycolide.

  PGA can be synthesized by dehydration polycondensation of glycolic acid, dealcoholization polycondensation of glycolic acid alkyl ester, ring-opening polymerization of glycolide, and the like. Among these, glycolide is heated to a temperature of about 120 ° C. to about 250 ° C. in the presence of a small amount of a catalyst (for example, a cationic catalyst such as tin organic carboxylate, tin halide, antimony halide, etc.) to open a ring. A method of synthesizing PGA by a polymerization method is preferred.

  That is, as PGA contained in the support film of the present invention, in order to efficiently produce a desired high molecular weight polymer, 70-100% by mass of glycolide and 30-0% by mass of other cyclic monomers are subjected to ring-opening polymerization. PGA obtained is preferable. The other comonomer may be a cyclic monomer between two molecules, or may be a mixture of both instead of the cyclic monomer, but a cyclic monomer is preferred for the support film of the present invention.

  Hereinafter, PGA obtained by ring-opening polymerization of 70 to 100% by mass of glycolide and 30 to 0% by mass of other cyclic monomers will be described in detail.

[Glycolide]
Glycolide that forms PGA by ring-opening polymerization is a bimolecular cyclic ester of glycolic acid, which is a kind of hydroxycarboxylic acid. Although the manufacturing method of glycolide is not specifically limited, Generally, it can obtain by thermally depolymerizing a glycolic acid oligomer. As a depolymerization method for glycolic acid oligomers, for example, a melt depolymerization method, a solid phase depolymerization method, a solution depolymerization method, etc. can be adopted, and glycolide obtained as a cyclic condensate of chloroacetate should also be used. Can do. If desired, glycolide containing glycolic acid can be used up to 20% by mass of the glycolide amount.

  The PGA contained in the support film of the dry film resist of the present invention may be formed by ring-opening polymerization of only glycolide. However, the copolymer may be formed by simultaneously ring-opening polymerization using another cyclic monomer as a copolymerization component. It may be formed. In the case of forming a copolymer, the proportion of glycolide is 70% by mass or more, preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 98% by mass. % Or more, most preferably 99% by weight or more of a substantially PGA homopolymer.

[Cyclic monomer]
Other cyclic monomers that can be used as a copolymerization component with glycolide include lactones (for example, β-propiolactone, β-butyrolactone, in addition to bimolecular cyclic esters of other hydroxycarboxylic acids such as lactide). Cyclic monomers such as pivalolactone, γ-butyrolactone, δ-valerolactone, β-methyl-δ-valerolactone, ε-caprolactone, trimethylene carbonate, 1,3-dioxane and the like can be used. Other preferable cyclic monomers are bimolecular cyclic esters of other hydroxycarboxylic acids. Examples of hydroxycarboxylic acids include L-lactic acid, D-lactic acid, α-hydroxybutyric acid, α-hydroxyisobutyric acid, α- Hydroxyvaleric acid, α-hydroxycaproic acid, α-hydroxyisocaproic acid, α-hydroxyheptanoic acid, α-hydroxyoctanoic acid, α-hydroxydecanoic acid, α-hydroxymyristic acid, α-hydroxystearic acid, and these Examples include alkyl-substituted products. Another particularly preferable cyclic monomer is lactide, which is a bimolecular cyclic ester of lactic acid, and may be any of L-form, D-form, racemate, and a mixture thereof.

  The other cyclic monomer is 30% by mass or less, preferably 20% by mass or less, more preferably 10% by mass or less, further preferably 5% by mass or less, particularly preferably 2% by mass or less, and most preferably 1% by mass or less. Used in proportions. By ring-opening copolymerization of glycolide and other cyclic monomers, the melting point of PGA (copolymer) is lowered to lower the molding temperature, and the crystallization rate is controlled to improve extrusion processability and stretch processability. can do. However, if the use ratio of these cyclic monomers is too large, the crystallinity of the formed PGA (copolymer) may be impaired, and heat resistance, mechanical strength, and the like may be reduced. In addition, when PGA is formed from glycolide 100 mass%, another cyclic monomer is 0 mass%, and this PGA is also included in the scope of the present invention.

(Ring-opening polymerization reaction)
The ring-opening polymerization or ring-opening copolymerization of glycolide (hereinafter sometimes collectively referred to as “ring-opening (co) polymerization”) is preferably carried out in the presence of a small amount of a catalyst. Although the catalyst is not particularly limited, for example, a tin-based compound such as tin halide (for example, tin dichloride, tin tetrachloride, etc.) or organic carboxylate (for example, tin octoate such as tin 2-ethylhexanoate). A titanium compound such as alkoxy titanate; an aluminum compound such as alkoxyaluminum; a zirconium compound such as zirconium acetylacetone; an antimony compound such as antimony halide and antimony oxide; The usage-amount of a catalyst is a mass ratio with respect to cyclic ester, Preferably it is 1-1000 ppm, More preferably, it is about 3-300 ppm.

  Glycolide usually contains a trace amount of water and a hydroxycarboxylic acid compound composed of glycolic acid and a linear glycolic acid oligomer as impurities. By adjusting the total proton concentration of these impurities to preferably 0.01 to 0.5 mol%, more preferably 0.02 to 0.4 mol%, particularly preferably 0.03 to 0.35 mol%. The physical properties such as melt viscosity and molecular weight of the produced PGA can be controlled. Adjustment of the total proton concentration can also be performed by adding water to the purified glycolide.

  The ring-opening (co) polymerization of glycolide may be bulk polymerization or solution polymerization, but in many cases, bulk polymerization is employed. In order to adjust the molecular weight, a higher alcohol such as lauryl alcohol or water can be used as the molecular weight regulator. Moreover, you may add polyhydric alcohols, such as glycerol, for a physical property improvement. There are various types of polymerization equipment for bulk polymerization, such as an extruder type, a vertical type with paddle blades, a vertical type with helical ribbon blades, a horizontal type such as an extruder type and a kneader type, an ampoule type, a plate type and a tubular type. The device can be selected as appropriate. Moreover, various reaction tanks can be used for solution polymerization.

  The polymerization temperature can be appropriately set according to the purpose within a range from 120 ° C. to 300 ° C. which is a substantial polymerization start temperature. The polymerization temperature is preferably 130 to 270 ° C, more preferably 140 to 260 ° C, and particularly preferably 150 to 250 ° C. If the polymerization temperature is too low, the molecular weight distribution of the produced PGA tends to be wide. If the polymerization temperature is too high, the produced PGA is susceptible to thermal decomposition. The polymerization time is in the range of 3 minutes to 20 hours, preferably 5 minutes to 18 hours. If the polymerization time is too short, the polymerization does not proceed sufficiently and a predetermined weight average molecular weight cannot be realized. If the polymerization time is too long, the produced PGA tends to be colored.

  After making the produced PGA into a solid state, solid phase polymerization may be further carried out if desired. The solid-phase polymerization means an operation of performing heat treatment while maintaining a solid state by heating at a temperature lower than the melting point (Tm) of PGA. By this solid phase polymerization, low molecular weight components such as unreacted monomers and oligomers are volatilized and removed. The solid phase polymerization is preferably performed for 1 to 100 hours, more preferably 2 to 50 hours, and particularly preferably 3 to 30 hours.

  Further, the crystallinity may be controlled by giving a thermal history to the solid PGA by a step of melting and kneading the PGA in a melting point Tm + 38 ° C. or higher, preferably within a temperature range from Tm + 38 ° C. to Tm + 100 ° C.

[Weight average molecular weight (Mw)]
The weight average molecular weight (Mw) of PGA obtained by these polymerization methods is in the range of 25,000 to 800,000, preferably 50,000 to 700,000, more preferably 80,000 to 600, 000, more preferably 120,000 to 500,000, particularly preferably 150,000 to 400,000.

[Melting point (Tm)]
The melting point (Tm) of PGA contained in the support film of the dry film resist of the present invention is 197 to 245 ° C., and can be adjusted by the type and content ratio of the copolymer component. Preferably it is 200-243 degreeC, More preferably, it is 205-238 degreeC, Most preferably, it is 210-235 degreeC. The melting point of the homopolymer of PGA is usually about 220 ° C. If the melting point is too low, the mechanical strength is insufficient, or the temperature control when performing the molding process becomes difficult. If the melting point is too high, the processability may be insufficient or the flexibility of the film may be insufficient. On the other hand, if the melting point is too high, the molding temperature becomes high, so that PGA and other additive components may be thermally decomposed and oxidized.

[Crystallization temperature ( _TC1 )]
Crystallization temperature of the PGA contained in the support film of the dry film resist of the present invention _{(T C1)} is usually 75 to 100 ° C., preferably 80 to 97 ° C., more preferably 85 to 95 ° C., particularly preferably It is 88-93 degreeC. The crystallization temperature (T _C1 ) of PGA is such that the sample PGA is heated from 50 ° C. to about 250 ° C. at a heating rate of 10 ° C./min, held at this temperature for 2 minutes, and then rapidly (about 100 Amorphous sample obtained by cooling to ℃ / min) is detected in the process of reheating using a differential scanning calorimeter (DSC) from -50 ℃ to 10 ℃ / min in a nitrogen atmosphere. Means the temperature of the exothermic peak due to crystallization. If the melt crystallization temperature (T _C1 ) is too high, in the production process of the support film of the present invention, crystallization starts early, an unstretched film cannot be obtained, and mechanical strength and surface due to subsequent stretching operations, etc. The property cannot be controlled. When the crystallization temperature (T _C1 ) is too low, coarse PGA crystals are formed, and the mechanical strength may be lowered. The melt crystallization temperature (T _C1 ) can be adjusted by appropriately selecting the molecular weight of PGA and the type and amount of the polymerization component. It is also possible to control the melt crystallization temperature (T _C1 ) by giving a thermal history to the solid state PGA by a melt kneading step within the temperature range of the melting point Tm + 38 ° C. or more, preferably Tm + 38 ° C. to Tm + 100 ° C. it can.

[Melt viscosity]
The melt viscosity of PGA contained in the support film of the dry film resist of the present invention is preferably 100 to 2,000 Pa · s, more preferably measured at a temperature of 270 ° C. and a shear rate of 122 sec ^−1. 200 to 1,500 Pa · s, more preferably 250 to 1,000 Pa · s. When the melt viscosity of PGA at 270 ° C. and 122 sec ⁻¹ is less than 100 Pa · s, the molecular weight of PGA is low, and there is a risk of decomposition during use. Also, if the melt viscosity exceeds 2,000 Pa · s, there may be a problem that the load on the extruder and the filtration pressure increase in the polymer extrusion process, or lamination by co-extrusion with a film containing another polymer is difficult. There is a risk of becoming.

2. Support Film The support film of the dry film resist of the present invention is a film containing PGA having a glycolic acid repeating unit represented by the formula — (O · CH ₂ · CO) — of 70 mol% or more (hereinafter simply referred to as “PGA-containing”). At least one layer ”.

  Therefore, as the support film of the present invention, a dry film resist support film which is a single layer film containing the PGA, and a dry film resist support film which is a laminated film including the film containing the PGA and other polymers. Any of these may be used.

[Other resins and additives]
In addition to PGA, inorganic fillers, other thermoplastic resins, plasticizers, and the like can be blended with the PGA-containing film as long as the object of the present invention is not impaired.

For example, polylactic acid (hereinafter sometimes referred to as “PLA”), polybutylene succinate, polyethylene succinate, polyβ-propiolactone, polycaprolactone, and other aliphatic polyesters, polyethylene glycol, polypropylene glycol, and the like. Other thermoplastic resins such as glycols, modified polyvinyl alcohol, polyurethane, and polyamides such as poly L-lysine can be blended as necessary. From the viewpoint of adjusting the degradability such as biodegradability, it is preferable to add PLA.
Since these contents are within a range in which the transmission of actinic rays such as ultraviolet rays is not inhibited and the light transmittance is maintained, 30% by mass when all the components of the film containing PGA are 100% by mass. % Or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less.

  In addition, a film containing PGA usually contains a heat stabilizer, a light stabilizer, a moisture proof agent, a waterproofing agent, a water repellent, a lubricant, a release agent, a coupling agent, an oxygen absorber, and the like as necessary. Various additives to be added can be contained.

  These contents are within a range that does not hinder the object of the present invention as described above, and in particular, are within a range that does not hinder the transmission of actinic rays such as ultraviolet rays and can maintain light transmittance. Specifically, when the total component of the film containing PGA is 100% by mass, it is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 2% by mass or less.

[Support film as a laminated film]
The support film in the dry film resist of the present invention may be a laminated film of a film containing the PGA and a film containing another polymer. The support film which is a laminated film is arranged so that the film containing PGA is in contact with the resist layer. The film containing another polymer is not limited as long as the laminated film can maintain light transmission, and aromatic polyester, aliphatic polyester, acrylic resin, polyolefin, and the like can be used. The other polymer is preferably at least one selected from the group consisting of PLA which is an aliphatic polyester and polyethylene terephthalate which is an aromatic polyester.

  When the other polymer is PLA, the entire support film can be made degradable. The PLA may be a copolymer containing other monomer units other than lactic acid in addition to PLA polymerized using L-lactic acid and / or D-lactic acid as main constituent components. Other monomer units include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, pentaerythritol, bisphenol A. Glycol compounds such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol; oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid , Naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4′-diphenyl ether dicarboxylic acid Dicarboxylic acids such as 5-sodium sulfoisophthalic acid and 5-tetrabutylphosphonium isophthalic acid; hydroxycarboxylic acids such as glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid; caprolactone, valerolactone And lactones such as propiolactone, undecalactone, and 1,5-oxepan-2-one.

  When the other polymer is polyethylene terephthalate (hereinafter sometimes referred to as “PET”), the mechanical strength of the support film is improved. As PET, in addition to the PET homopolymer, a copolymer in which 80 mol% or more of all dicarboxylic acid components are terephthalic acid and 80 mol% or more of all glycol components is ethylene glycol can be used. That is, 20 mol% or less of the total acid component is aromatic such as isophthalic acid, naphthalene dicarboxylic acid, diphenylethane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid, diphenyl ketone dicarboxylic acid, anthracene dicarboxylic acid Dicarboxylic acid; aliphatic dicarboxylic acid such as adipic acid and sebacic acid; alicyclic carboxylic acid such as cyclohexane-1,4-dicarboxylic acid and the like. In addition, 20 mol% or less of all glycol components are glycols such as trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, decamethylene glycol; hydroquinone, resorcin, 2,2-bis (4-hydroxydiphenyl) An aromatic diol such as propane; an aliphatic diol having an aromatic ring such as 1,4-dihydroxymethylbenzene; a polyalkylene glycol (polyoxyalkylene glycol) such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. it can. From the viewpoint of adhesiveness with a film containing PGA and transparency, a copolymer is preferably used.

  In the film containing other polymers, in addition to PGA, inorganic fillers, other thermoplastic resins, plasticizers, heat stabilizers, light stabilizers, moisture-proofing agents, waterproofing agents, as long as the object of the present invention is not impaired. Various additives usually blended such as a water repellent, a lubricant, a release agent, a coupling agent, an oxygen absorbent, a pigment and a dye can be blended.

  The content of the other polymer that is at least one selected from the group consisting of PLA and PET is preferably 50% by mass or more when the total component of the film containing the other polymer is 100% by mass. More preferably, it is 70 mass% or more, More preferably, it is 80 mass% or more, Most preferably, it is 90 mass% or more.

  As described above, since the support film which is a laminated film is arranged so that the film containing PGA is in contact with the resist layer, when a film containing another polymer is arranged in the outermost layer, By incorporating inorganic or organic fine particles having an average particle size of 0.01 to 3.0 μm into the film, the surface slipperiness, winding property and scratch resistance can be improved.

[Thickness of support film]
The thickness of the support film of the dry film resist of the present invention is usually in the range of 5 to 50 μm, preferably 8 to 45 μm, more preferably 10 to 40 μm, and particularly preferably 12 to 35 μm. If the thickness of the support film is less than 5 μm, the film is too soft and inconvenient to handle, and if the thickness exceeds 50 μm, the followability to the unevenness of the substrate and the resolution may be reduced.

  When the support film is a laminated film of a film containing PGA and a film containing another polymer, the thickness of the film containing PGA is usually 1 to 95% with respect to the thickness of the entire laminated film, Preferably it is 5 to 90%, More preferably, it is 10 to 85%, Most preferably, it is 20 to 80%, Most preferably, it is the range of 30 to 75%. If the ratio of the thickness of the film containing PGA is less than 1%, peeling from the resist layer may not be easy, or the resolution may be reduced. When the thickness ratio of the film containing PGA exceeds 95%, the cost increases.

[Manufacture of support film]
The film containing the PGA, which is a support film for the dry film resist of the present invention, is formed by melting the PGA, stretching it uniaxially or biaxially as desired, and further heat-treating it. As methods and conditions for these steps, known methods and conditions can be employed. For example, using an extrusion molding machine equipped with a slit-shaped die, PGA is melt-kneaded at a temperature of melting point Tm to 300 ° C. and extruded into a sheet, and is lower than the crystallization temperature T _C1 , usually 5 to 70 ° C., many In the case of forming a non-stretched sheet by quenching and solidifying with a cooling drum maintained at a surface temperature in the range of 10-50 ° C., and stretching the unstretched sheet at a temperature of 30-70 ° C., preferably 33-68 ° C., More preferably, uniaxial stretching or sequential or simultaneous biaxial stretching is performed at a temperature of 35 to 65 ° C. at an area magnification of 2 to 100 times, preferably 4 to 60 times, more preferably 6 to 30 times, and then 130 Heat treatment is performed at a temperature of ˜210 ° C., preferably 140 ° C. to 200 ° C. under tension or under 20% relaxation. In order to produce a stretched film, a method in which a stretching roll and a tenter stretching machine are combined is employed. When performing sequential biaxial stretching, after stretching uniaxially in the machine direction (MD) using a stretching roll, After performing cooling or heat treatment as necessary, it is preferable to stretch in the transverse direction (TD) using a tenter stretching machine.

  As a method for producing a support film which is a laminated film, a method of adhering a film containing the PGA obtained by melt film formation and a film containing another polymer with an adhesive, coextrusion or extrusion lamination Although a laminated film can be produced by a known method such as a method for producing a laminated film, it is preferable to obtain a laminated film by coextrusion. In the case of producing a support film that is a laminated film that has been subjected to stretching treatment, it is preferable to obtain a laminated film in advance, followed by uniaxial or biaxial stretching treatment and heat treatment.

3. Dry film resist The dry film resist of the present invention comprises a support film comprising at least one film containing PGA, and a resist layer on at least one side of the support film, and, if desired, a support film for the resist layer. It has a protective film on the side opposite to the side.

(1) Resist layer The resist layer in the dry film resist of the present invention is not particularly limited as long as it is a photosensitive resin composition that can be cured by actinic rays such as visible light and ultraviolet rays. Can do. For example, the thing containing a photosensitive prepolymer (base polymer), an ethylenically unsaturated compound, and a photoinitiator is used.

  As the photosensitive prepolymer, those having an ethylenically unsaturated end group derived from an acrylic monomer are preferably used. The acrylic monomer here is acrylic acid or methacrylic acid, or a derivative thereof such as an alkyl ester or a hydroxyalkyl ester. Examples of such photosensitive prepolymer include prepolymers such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, polybutadiene (meth) acrylate, silicone (meth) acrylate, and melamine (meth) acrylate. Of these, prepolymers of epoxy (meth) acrylate and urethane (meth) acrylate are preferred. “(Meth) acrylate” means “acrylate” or “methacrylate”.

  The ethylenically unsaturated compound in the photosensitive resin composition is other than the photosensitive prepolymer, and adjusts the viscosity of the photosensitive resin composition, or heat resistance when the photosensitive resin composition is a cured product, Used for the purpose of adjusting physical properties such as flexibility. As the ethylenically unsaturated compound, an ester of acrylic acid or methacrylic acid is preferably used. Specifically, alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and butyl (meth) acrylate; cyclohexyl (meth) acrylate, dicyclopentenyl (meth) acrylate and the like Cycloaliphatic (meth) acrylates; aromatic (meth) acrylates such as benzyl (meth) acrylate, phenyl (meth) acrylate, phenyl carbitol (meth) acrylate; 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) ) Acrylate, polyethylene glycol (meth) acrylate, (meth) acrylate having a hydroxyl group such as glycerol di (meth) acrylate; amino group such as 2-dimethylaminoethyl (meth) acrylate (Meth) acrylate having: methacrylate having phosphorus atom such as methacryloxyethyl phosphate; diacrylate such as ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate and triethylene glycol di (meth) acrylate; trimethylolpropane Polyacrylates such as tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate; ethylene oxide 4 mol modified diacrylate of bisphenol A, propylene oxide 3 mol modified triacrylate of trimethylolpropane, etc. Examples include modified polyol polyacrylates; polyacrylates having an isocyanuric acid skeleton; and polyester acrylates. Further, N-vinyl compounds such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, polyester acrylate, urethane acrylate, epoxy acrylate, and the like can also be suitably used as the ethylenically unsaturated compound. Among these, (meth) acrylate having a hydroxyl group, glycidyl (meth) acrylate, trimethylolpropane tri (meth) acrylate and urethane acrylate are preferable.

  The compounding ratio of the photosensitive prepolymer and the ethylenically unsaturated compound is in the range of 95: 5 to 50:50, preferably 90:10 to 55:45, more preferably 85:15 to 58:42 by mass ratio. is there. When the blending amount of the photosensitive prepolymer exceeds 95% by mass, the solder heat resistance of the cured film formed from the photosensitive resin composition may be lowered. When the blending amount of the photosensitive prepolymer is less than 50% by mass, the alkali solubility of the photosensitive resin composition tends to decrease.

  Examples of the photopolymerization initiator used in the present invention include benzophenones such as benzophenone, benzoylbenzoic acid, and 4-phenylbenzophenone; benzoin alkyl ethers such as benzoin, benzoin ethyl ether, and benzoin isopropyl ether; 4-phenoxydichloroacetophenone, Acetophenones such as 4-t-butyl-dichloroacetophenone, diethoxyacetophenone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, thioxanthene, 2-chlorothioxanthene, etc. Alkyl anthraquinones such as thioxanthenes, ethyl anthraquinone and butyl anthraquinone, and acyl phosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide Etc. can be mentioned. These can be used alone or as a mixture of two or more. Furthermore, if necessary, a photosensitizer can be used in combination.

  Of these photopolymerization initiators, benzophenones, acetophenones, and acylphosphine oxides are preferred. Specific examples include benzophenone and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2,4,6-trimethylbenzoyldiphenylphosphine oxide.

  The blending amount of these photopolymerization initiators is preferably 0.1 to 20 parts by mass with respect to a total of 100 parts by mass of the photocuring component composed of the photosensitive prepolymer and the compound having an ethylenically unsaturated group. 0.2 parts by mass to 10 parts by mass is more preferable. Curing may become inadequate when the compounding quantity of a photoinitiator is less than 0.1 mass part.

  The photosensitive resin composition that is the resist layer of the dry film resist of the present invention may contain other components as necessary.

  For example, a flame retardant may be added to the photosensitive resin composition in order to impart flame resistance to the resist layer. Flame retardants include halide flame retardants such as brominated epoxy compounds, hydrated metal compounds such as aluminum hydroxide and magnesium hydroxide, phosphorus flame retardants such as phosphate ester compounds and ammonium polyphosphate, antimony trioxide, etc. Flame retardant aids and the like.

  Moreover, you may add and use an organic solvent for the photosensitive resin composition as needed for viscosity adjustment. By adjusting the viscosity, coating on the support film is facilitated with a knife coater, blade coater, slit orifice coater, roller coater, spin coater, screen coater, curtain coater or the like.

  In order to adjust fluidity, a flow modifier can be further added to the photosensitive resin composition. For example, when the photosensitive resin composition is applied onto a support film by roller coating, spin coating, screen coating, curtain coating, or the like, the flow modifier is preferable because the fluidity of the photosensitive resin composition can be appropriately adjusted. Examples of the flow regulator include inorganic or organic fillers such as talc, barium sulfate, aluminum hydroxide, silicone resin, and fluororesin, wax, surfactants, and the like.

  A dye or pigment colorant can be further added to the photosensitive resin composition. Examples of the colorant include phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black, and naphthalene black.

  Moreover, the thermal resin inhibitor, a thickener, an antifoamer, a leveling agent, and the adhesive imparting agent can be added to the photosensitive resin composition as necessary.

  The photosensitive resin composition can be produced by mixing each of the above components by a usual method. The mixing method is not particularly limited, and a part of the components may be mixed and then the remaining components may be mixed, or all the components may be mixed at once. It is preferable to knead or pulverize the agglomerated particles after mixing the above-mentioned components, for example, known kneading such as a Banbury mixer, a kneader, a roll, a single or twin screw extruder, a kneader, a three roll, and a bead mill. It is manufactured by using a pulverizer or a pulverizer.

  The thickness of the resist layer made of the photosensitive resin composition is, after drying, typically 10 to 100 μm, preferably 20 to 90 μm, more preferably 30 to 80 μm.

(2) Protective film The dry film resist of the present invention has a support film and a resist layer on at least one side of the support film. In order to protect the resist layer, the resist film on the support film side of the resist layer is used. It is preferable to have a protective film on the opposite side.

  As the protective film, a plastic film or a film provided with a release layer on the side in contact with the resist layer of the plastic film can be used. As the plastic film, a polyester film, a polyolefin film, a polyamide film or the like can be used, and particularly preferred are a polyester film and a polypropylene film. Examples of the constituent component of the release layer include a silicone compound and a wax composition, and a silicone compound is particularly preferable. As a method for providing the release layer on the protective film, a conventionally known coating method such as reverse roll coating, gravure coating, bar coating, doctor blade coating, or the like can be used.

  Although it will not specifically limit if the thickness of a protective film is a range which can be formed into a film as a film, It is preferable that it is the range of 5-50 micrometers, More preferably, it is the range of 12-30 micrometers. If the thickness of the protective film is less than 5μ, handling when peeling the protective film becomes difficult. If the thickness exceeds 50μm, the film is stiff, and when the protective film is peeled off, the resist layer surface is damaged. There is a risk that. The thickness of the release layer is 0.005 μm to 2 μm, preferably 0.01 μm to 0.5 μm. When the thickness of the release layer is less than 0.005 μm, sticks tend to be generated. When the thickness of the release layer exceeds 2 μm, the blocking resistance may be insufficient.

(3) Method for Producing Dry Film Resist The dry film resist of the present invention is produced by sequentially laminating a resist layer and, if desired, a protective film layer on a support film, which is a film containing PGA, by a conventional method. Can do. That is, for example, the dry film resist of the present invention is a resist layer in which a solution of a photosensitive resin composition (including a solvent such as an organic solvent) is first applied on a support film, and the solvent is removed by heating and drying. Is formed and manufactured. Next, if desired, a dry film resist may be obtained by laminating a protective film on the resist layer. At this time, when the release layer is applied and formed on the protective film, the protective film is bonded so that the side of the release layer is in contact with the resist layer. The dry film resist can be wound up into a roll. When making it into a roll-shaped product, it is preferable from the point of subsequent handling property to wind up so that a support film may become an outer side.

(4) Circuit board manufacturing method In order to form an image of a circuit pattern with a dry film resist, when the dry film resist has a protective film, the protective film is peeled off, and the resist layer side is coated with a copper-clad substrate or After affixing to a metal surface such as SUS or 42 alloy, a negative film (photomask) on which a predetermined pattern is formed is brought into close contact with the support film and exposed to actinic rays to form a photosensitive resin composition for the resist layer. The object is cured in a predetermined pattern. The exposure is usually performed by irradiating ultraviolet rays having a wavelength of about 193 to 400 nm. As the light source at that time, ArF excimer laser, KrF excimer laser, high pressure mercury lamp, super high pressure mercury lamp, carbon arc lamp, xenon lamp, metal halide lamp Chemical lamps and the like are used. In the present invention, since the ultraviolet transmittance of the PGA film provided in the support film is high even in the short wavelength region, actinic rays having the above-mentioned wavelength range from the far ultraviolet light to the near ultraviolet light can be used. After the ultraviolet irradiation, heating can be performed as necessary to complete the curing.

  After removing the negative film (photomask), the uncured photosensitive resin composition of the resist layer is removed, and development is performed to leave the cured photosensitive resin composition in a predetermined pattern. Development is performed by removing the uncured photosensitive resin composition of the resist layer using a weak alkaline aqueous solution of about 0.5 to 5% by mass such as sodium hydroxide, sodium carbonate, potassium carbonate, etc. Expose the layer. In the alkaline aqueous solution, a surfactant, an antifoaming agent, a small amount of an organic solvent for accelerating development, and the like may be mixed.

  Prior to development processing using a weak alkaline aqueous solution, a step of peeling and removing the support film of the dry film resist may be provided. However, since the dry film resist of the present invention includes a film containing alkali-decomposable PGA as a support film, the step of peeling and removing the support film is omitted, and the uncured photosensitive layer of the resist layer is removed with a weak alkaline aqueous solution. The support film can be removed together with the conductive resin composition.

  Subsequently, etching is performed to remove exposed metals such as copper foil. Etching is usually performed according to a conventional method using an acidic etching solution such as cupric chloride-hydrochloric acid aqueous solution or ferric chloride-hydrochloric acid aqueous solution. An ammonia-based alkaline etching solution can also be used.

  Next, the hardened resist is removed with a strong alkaline aqueous solution, a predetermined pattern is formed with a metal such as a copper foil, a plating process is performed as necessary, and a circuit with a predetermined pattern is formed with a metal such as a copper foil. Get. In the plating method, pretreatment is performed using a plating pretreatment agent such as a degreasing agent or a soft etching agent, and then plating is performed using a plating solution. As the strong alkaline aqueous solution, an alkaline aqueous solution having a concentration of about 1 to 10% by mass such as sodium hydroxide or potassium hydroxide is used.

  The dry film resist of the present invention is useful not only for the production of printed wiring boards and lead frames, but also for precision metal processing.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to these examples.

[Reference Example] Support film: Production of PGA biaxially stretched film PGA homopolymer was used as PGA. This PGA has a melting viscosity of 600 Pa · s measured at a melting point of 221 ° C., a crystallization temperature T _{C1 of} 90 ° C., a temperature of 270 ° C. and a shear rate of 122 sec ⁻¹ , and as a thermal stabilizer, Adeka Stab AX- manufactured by Asahi Denka Co., Ltd. 71 (monostearyl phosphate 50 mol% and distearyl phosphate 50 mol%) is contained at a ratio of 300 ppm.

  This PGA raw material pellet was heated and melted using a single screw extruder having a screw diameter of 35 mm so that the resin temperature was 260 to 270 ° C. The melt was cooled by casting through a 100 μm aperture filter from a T-die having a linear lip with a length of 270 mm and a gap of 0.75 mm, and cast on a metal drum whose surface was kept at 40 ° C., with a thickness of 200 μm. An unstretched sheet was prepared. The unstretched sheet was adjusted to a sheet temperature of 60 ° C., and uniaxially stretched in the machine direction (MD) at a stretching speed of 2 m / min using a stretching roll so that the stretching ratio was 6.0 times. The uniaxially stretched film is cooled using a spot cooler and a cooling roll so that the surface temperature is 33 ° C., and then introduced into a tenter stretching machine, and the film temperature is 38 ° C. and the stretching ratio is 3.7 times. In the tenter extruder, the biaxially stretched film was immediately subjected to heat treatment in a dry heat atmosphere at a temperature of 145 ° C. with a 5% relaxation in the width direction, and a thickness of 15 μm. An axially stretched film was produced.

Example 1
A photosensitive resin composition having the composition shown in Table 1 was prepared and applied uniformly to a PGA biaxially stretched film manufactured according to the reference example using a bar coater so that the thickness after drying was 50 μm, and then at 60 ° C. Drying was performed for 24 hours to produce a dry film resist having a PGA film and a resist layer.

  The obtained dry film resist was irradiated with ultraviolet rays having a wavelength of 385 nm from the PGA film side at a lamp position of 20 cm, an output of 120 W / cm, and a conveyor speed of 2 m / min, using an ultraviolet irradiation device manufactured by Nippon Battery Co., Ltd. The photosensitive resin composition of the resist layer was cured.

  About the dry film resist which hardened the resist layer, the peeling strength measurement between a PGA film and a resist layer was performed. Measurement is conducted using Tensilon RTC-1210A manufactured by Orientec Co., Ltd., in accordance with JIS Z0237, with a sample width of 15 mm and a tensile speed of 300 mm / min. A test was conducted. The results are shown in Table 2. In addition, adhesion of the cured resist layer was not seen at all on the peeled PGA film.

(Comparative Example 1)
A dry film resist was formed in the same manner as in Example 1 except that a 15 μm thick polyethylene terephthalate (hereinafter referred to as “PET”) biaxially stretched film (Lumirror P60, manufactured by Toray Industries, Inc.) was used as the support film. Manufactured and subjected to a 90 ° peel test. The results are shown in Table 2. In addition, the cured resist layer might have adhered partially to the peeled PET film.

  From Table 2, it can be seen that the dry film resist of the present invention requires only a small force to peel the PGA film as the support film from the cured resist layer. On the other hand, in the dry film resist of Comparative Example 1 using a PET film that has been widely used as a support film in the dry film resist as a support film, a large force is required to peel the support film from the cured resist layer. You can see that it is needed.

[Experimental Example 1] Evaluation of alkali decomposability An aqueous alkali solution having a sodium hydroxide concentration of 2 mass%, 5 mass% and 10 mass% was prepared, 100 ml of the alkaline aqueous solution was placed in an Erlenmeyer flask, and a magnetic stirrer was used using a water bath. With stirring at 50 ° C. or 60 ° C. In this Erlenmeyer flask, after the PGA film produced in the reference example, the PET film used in Comparative Example 1 and the dry film resist produced in Example 1 were irradiated with ultraviolet rays to cure the resist layer, the PGA The film was peeled off, and samples cut into 4 cm × 4 cm from the cured resist layer were respectively immersed. The time until each sample disappeared visually was measured as the time until complete decomposition. The results are shown in Table 3.

  From Table 3, it can be seen that the film containing the PGA of the present invention used for the dry film resist disappears in a short time by the alkaline aqueous solution. On the other hand, it can be seen that the PET film that has been widely used as a support film in the dry film resist is substantially impossible to remove with an alkaline aqueous solution.

  In addition, since the cured resist layer is not substantially removed under the alkaline conditions in Experimental Example 1, in the manufacture of the circuit board, development is performed to remove the uncured resist layer with an alkaline aqueous solution after exposure. When performing, since the process of peeling off the support film can be omitted, it can be seen that the manufacturing efficiency of the circuit board and the like can be improved and the manufacturing cost can be reduced.

[Experimental Example 2] Ultraviolet Transmittance Test For the PGA film produced in the reference example and the PET film used in Comparative Example 1, the transmittance of ultraviolet rays having different wavelengths was measured for each wavelength using a spectrophotometer UV2450 manufactured by Shimadzu Corporation. Measured. The results are shown in Table 4.

  From Table 4, the film containing the PGA of the present invention used for the dry film resist has a high ultraviolet transmittance as compared with the PET film that has been widely used as a support film in the dry film resist. Since the layer can be cured, it can be seen that the manufacturing efficiency of the circuit board and the like can be improved and the manufacturing cost can be reduced. Moreover, it turns out that the film containing PGA of this invention has the high transmittance | permeability with respect to the ultraviolet-ray of a shorter wavelength area | region whose wavelength of 300 micrometers or less which is not permeate | transmitted especially by PET film. Therefore, if the dry film resist of the present invention is used, the resist layer can be cured by irradiating with ultraviolet rays having a shorter wavelength, so that a more detailed circuit pattern can be provided and the circuit of the printed wiring board can be finely patterned. It is possible to meet the demands for higher resolution such as the development of applications, application to liquid crystal display wiring, and direct mounting of semiconductors.

In the dry film resist having a support film, a resist layer, and optionally a protective film of the present invention, the support film has 70 mol% or more of a glycolic acid repeating unit represented by the formula — (O · CH ₂ · CO) —. By providing a film containing polyglycolic acid, a circuit board can be produced more efficiently and at a lower cost, and a dry film that can meet the demand for higher resolution is provided. Therefore, the industrial applicability is high. Moreover, since the support film can be made degradable, the environmental load is small and the industrial utility is high.

Claims (8)

A support film, and a dry film resist having a resist layer on at least one side of the support film, wherein the support film has a glycolic acid repeating unit represented by the formula-(O.CH ₂ .CO)-at least 70 mol%. The dry film resist as described above, comprising at least one film containing polyglycolic acid.   The dry film resist of Claim 1 which has a protective film on the opposite side to the support film side of the said resist layer. The dry film according to claim 1 or 2, wherein the support film contains polylactic acid in addition to polyglycolic acid having 70 mol% or more of a glycolic acid repeating unit represented by the formula-(O · CH ₂ · CO)-. Film resist. The support film is a laminated film comprising a film containing polyglycolic acid having a glycolic acid repeating unit represented by the formula-(O.CH ₂ .CO)-and having 70 mol% or more, and a film containing another polymer. The dry film resist according to any one of claims 1 to 3.   The dry film resist according to claim 4, wherein the other polymer is at least one selected from the group consisting of polylactic acid and polyethylene terephthalate. Formula _{- (O · CH 2 · CO} ) - dry film resist supporting film according to any one of claims 1 to 3 containing glycolic acid repeating polyglycolic acid containing units 70 mol% or more represented by. 5. A laminated film comprising a film containing polyglycolic acid having a glycolic acid repeating unit represented by the formula — (O · CH ₂ · CO) — of 70 mol% or more, and a film containing another polymer. Or the support film for dry film resists of 5.   The manufacturing method of the circuit board which uses the dry film resist of any one of Claims 1 thru | or 5.